1. Field of the Invention
The present invention relates to a magnetic-head supporting mechanism for a magnetic-disc apparatus, and in particular, to a magnetic-head supporting mechanism that is excellent in impact resistance.
2. Description of the Related Art
It has been reported that when a large impact is applied to a conventional magnetic-disc apparatus in the direction perpendicular to a disc surface, a slider jumps up from the magnetic disc surface, is tilted while floating, and falls from the angle of a slider floating rail to contact and damage the disc surface (IEEE TRANSACTION ON MAGNETICS Vol. 31, No. 6, pp. 3006 to 3008: NOVEMBER, 1995). This article also reports that a “jump stop” is effectively provided on the slider in order to reduce the damage to the disc caused by an impact. In addition, JP-A-8-102159 discloses a mechanism comprising a pin protrusion (a limiter section) on a cover or on a base of a magnetic-disc apparatus wherein if the magnetic-disc apparatus is subjected to an impact to oscillate a suspension having a magnetic head at its free end, the free end of the suspension contacts the pin protrusion and is stopped from being further displaced toward the base or cover.
According to the conventional mechanism, if the slider is subjected to an impact and leaves the disc surface, the jump height is restricted by the jump stop or pin protrusion to a predetermined value or less. An object of this configuration is to reduce the speed or acceleration at which the slider collides against the disc in order to reduce the damage to the slider and disc upon the impact, thereby improving the impact resistance of the magnetic-disc apparatus.
On the other hand, the degree of damage depends on the magnitude of the speed and acceleration at which the slider contacts the disc as well as the extent of the contact area. That is, the contact area significantly varies depending on whether a floating surface (a surface that is opposed to the disc surface and on which a floating force is effected) of the slider contacts the disc surface in parallel or the slider rotates and contacts the disc surface at the corners of its floating surface or at its bleed surface (a surface that is opposed to the disc surface and on which a floating force is not effected). Thus, even if the slider contacts the disc surface at the same speed and acceleration, the contact area pressure (stress) significantly varies depending on the contact areas of the slider and disc surface, that is, the position of the slider in which it collides against the disc surface, resulting in significantly different degrees of damage. The prior art does not take this point into account.